The Effect of Decreased Protein Levels in Sow Diets on Nitrogen Content of Faeces and Physiological Parameters of Blood

The research material consisted of 42 sows divided into 3 feeding groups, 14 individuals in each group, which received feed mixtures with different protein levels. Protein and amino acid levels in the control group were in accordance with recommendations contained in Polish standards. The level of protein in experimental groups was decreased by 10 and 20%, respectively, and the levels of lysine, methionine, threonine and tryptophan were adjusted to those of the control group. During the gestation and lactation periods all sows were fed individually. The content of dry matter, nitrogen, fibre, fat and ash was determined in samples of faeces collected at 60 and 105 days of pregnancy, and the total nitrogen content was assessed in urine. Blood from sows was collected on day 14 of lactation, and indices of protein, fat transformation and mineral components content were determined in blood serum. The results of the analysis of faeces and urine prove that pregnant sows from the experimental groups excreted 7% and 10% less nitrogen in faeces, and 18% and 23% less urine in faeces. The reduced protein level in feed mixtures did not significantly influence the content of dry matter, fibre and ash in faeces. A significant decrease in the content of total protein, globulins, urea and an increase in cholesterol level was observed in the blood serum of sows from both experimental groups. No influence of the reduced protein level in feed on the content of mineral compounds in blood serum or haematological parameters of the sows' blood was noted.